1. Field of the Invention
This invention relates to antimicrobial compositions containing organo sulfonyl ethylene compounds and more particularly to antimicrobial solutions of organo sulfonyl ethylene compounds that are compatible with plastic polymers.
This invention further relates to antimicrobial compositions containing antimicrobial compounds selected from the group consisting of isoindole dicarboximides having a sulfur atom bonded to the nitrogen atom of the dicarboximide group, and zinc hydroxy-pyridine thionates. More particularly, this invention relates to antimicrobial solutions of antimicrobial compounds selected from the group consisting of isoindole dicarboximides having a sulfur atom bonded to the nitrogen atom of the dicarboximide group and zinc hydroxy-pyridine thionates, said antimicrobial solutions being compatible with plastic polymers.
2. Description of the Prior Art
To protect polymer compositions from attack by fungi and similar organisms, it is normal to add an antimicrobial compound to the polymeric composition. One class of antimicrobial compounds is organo sulfonyl ethylene compounds. These compounds are disclosed in U.S. Pat. Nos. 3,052,597; 3,199,990 and 3,471,571. The latter patent is directed to a process for preparing the compounds and the former two patents disclose the compound's utility as fungicides.
Many of the available microbiocidal materials are solid and, in order to incorporate them homogeneously in the resin composition, it is necessary first to mix them with a liquid which solubilizes or disperses the material uniformly and thereafter, mixing the liquid composition with the resin. Unfortunately, the solubility of many of the microbiologically active material in the common solvent materials is quite low. Therefore, it is either difficult to incorporate a sufficiently high concentration of the microbiocidal material with the resin or, if sufficiently high concentrations of the active material can be incorporated in the resin, an undesirably high concentration of the solvent also must be incorporated in the resin with the resultant deterioration of the desirable characteristics of the resin composition.
The same difficulty encountered with many of the more readily available antimicrobials in adding them to plastic polymers has been encountered with the organo sulfonyl ethylene compounds. The problem is an incompatibility that results in a poor blending manifested by what has been described as "blooming" and generally a tendency to separate with the biocide moving to the surface and causing surface defects and loss of the biocide.
One method of solving this problem of the incompatibility of the biocide and polymer is to solubilize the biocide in a solvent to form a biocidal solution which is compatible with the polymer. Thus, for example, Reissue Pat. No. 29,409 (reissue of U.S. Pat. No. 3,288,674) discloses that microbiocidal properties can be imparted to vinyl resins by the incorporation therein of a selected phenoxarsine compound dissolved in a solvent selected from phenols and monocarboxylic acids. Likewise, U.S. Pat. No. 4,049,822 discloses microbiocidal solutions for resins including a glycyl phosphite or glycyl phosphonate and a microbiologically active phenoxarsine compound. The microbiocidal solutions disclosed in Re. 29,409 and U.S. Pat. No. 4,049,822 may also include additional solvents, dispersants or resin plasticizers.